Removing Barrel Lock from UPVC Door

[Granty2]

Hi, I know this should be simple and I have looked up the info but I tried to remove my Mums lock to replace it yesterday, admittedly in a rush. The barrel pushed forward out of the door just over an inch and seemed to get stuck, I slowly revolved the key around what seemed like at least 3 full turns and it would not push out? I tried from the other side and exactly the same which made me wonder if I needed two keys as they don't turn in sync with each other though I guess this is normal for this type of lock?
Are these barrel locks all the same to remove? Pretty much all info I've come across states to turn roughly 10 degrees and it should come free.
I removed one retaining screw (phillips) just below is a star screw which I assume is for the metal strip that runs up the side of the door?
Can anybody offer any advice as to why I couldn't remove the barrel or should it come free with perseverance?
The only other info I can give is that the key enters at a 90 degree angle so would that still be a 10 degree turn? does it matter what position the lock is in? sorry I have only ever replaced standard locks prior to this.
Thanks in advance for any help as she urgently needs the lock repolacing due to someone having a key who shouldn't have.

 

[Brigade77]

 

[ronniecabers]

It may be the barrel is broken internally ... try using the key in the other side of the door. Only one key can be put into a Upvc Barrel lock at one time

You may also find that it is ' fouling ' on the door handles and is a tight fit in the door lock...try removing the handles and then when turning the key give the lock a good ' wiggle '